1/* Copyright 2018 Mozilla Foundation
2 *
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16use crate::{
17 BinaryReader, BinaryReaderError, FromReader, Result, SectionLimited, Subsection, Subsections,
18};
19use core::ops::Range;
20
21/// Represents a name map from the names custom section.
22pub type NameMap<'a> = SectionLimited<'a, Naming<'a>>;
23
24/// Represents a name for an index from the names section.
25#[derive(Debug, Copy, Clone)]
26pub struct Naming<'a> {
27 /// The index being named.
28 pub index: u32,
29 /// The name for the index.
30 pub name: &'a str,
31}
32
33impl<'a> FromReader<'a> for Naming<'a> {
34 fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
35 let index: u32 = reader.read_var_u32()?;
36 // This seems to match what browsers do where they don't limit the
37 // length of names in the `name` section while they do limit the names
38 // in the import and export section for example.
39 let name: &'a str = reader.read_unlimited_string()?;
40 Ok(Naming { index, name })
41 }
42}
43
44/// Represents a reader for indirect names from the names custom section.
45pub type IndirectNameMap<'a> = SectionLimited<'a, IndirectNaming<'a>>;
46
47/// Represents an indirect name in the names custom section.
48#[derive(Debug, Clone)]
49pub struct IndirectNaming<'a> {
50 /// The indirect index of the name.
51 pub index: u32,
52 /// The map of names within the `index` prior.
53 pub names: NameMap<'a>,
54}
55
56impl<'a> FromReader<'a> for IndirectNaming<'a> {
57 fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
58 let index: u32 = reader.read_var_u32()?;
59
60 // Skip the `NameMap` manually here.
61 //
62 // FIXME(#188) shouldn't need to skip here
63 let names: BinaryReader<'a> = reader.skip(|reader: &mut BinaryReader<'a>| {
64 let count: u32 = reader.read_var_u32()?;
65 for _ in 0..count {
66 reader.read_var_u32()?;
67 reader.skip_string()?;
68 }
69 Ok(())
70 })?;
71
72 Ok(IndirectNaming {
73 index,
74 names: NameMap::new(reader:names)?,
75 })
76 }
77}
78
79/// Represents a name read from the names custom section.
80#[derive(Clone)]
81pub enum Name<'a> {
82 /// The name is for the module.
83 Module {
84 /// The specified name.
85 name: &'a str,
86 /// The byte range that `name` occupies in the original binary.
87 name_range: Range<usize>,
88 },
89 /// The name is for the functions.
90 Function(NameMap<'a>),
91 /// The name is for the function locals.
92 Local(IndirectNameMap<'a>),
93 /// The name is for the function labels.
94 Label(IndirectNameMap<'a>),
95 /// The name is for the types.
96 Type(NameMap<'a>),
97 /// The name is for the tables.
98 Table(NameMap<'a>),
99 /// The name is for the memories.
100 Memory(NameMap<'a>),
101 /// The name is for the globals.
102 Global(NameMap<'a>),
103 /// The name is for the element segments.
104 Element(NameMap<'a>),
105 /// The name is for the data segments.
106 Data(NameMap<'a>),
107 /// The name is for fields.
108 Field(IndirectNameMap<'a>),
109 /// The name is for tags.
110 Tag(NameMap<'a>),
111 /// An unknown [name subsection](https://webassembly.github.io/spec/core/appendix/custom.html#subsections).
112 Unknown {
113 /// The identifier for this subsection.
114 ty: u8,
115 /// The contents of this subsection.
116 data: &'a [u8],
117 /// The range of bytes, relative to the start of the original data
118 /// stream, that the contents of this subsection reside in.
119 range: Range<usize>,
120 },
121}
122
123/// A reader for the name custom section of a WebAssembly module.
124pub type NameSectionReader<'a> = Subsections<'a, Name<'a>>;
125
126impl<'a> Subsection<'a> for Name<'a> {
127 fn from_reader(id: u8, mut reader: BinaryReader<'a>) -> Result<Self> {
128 let data = reader.remaining_buffer();
129 let offset = reader.original_position();
130 Ok(match id {
131 0 => {
132 let name = reader.read_string()?;
133 if !reader.eof() {
134 return Err(BinaryReaderError::new(
135 "trailing data at the end of a name",
136 reader.original_position(),
137 ));
138 }
139 Name::Module {
140 name,
141 name_range: offset..reader.original_position(),
142 }
143 }
144 1 => Name::Function(NameMap::new(reader)?),
145 2 => Name::Local(IndirectNameMap::new(reader)?),
146 3 => Name::Label(IndirectNameMap::new(reader)?),
147 4 => Name::Type(NameMap::new(reader)?),
148 5 => Name::Table(NameMap::new(reader)?),
149 6 => Name::Memory(NameMap::new(reader)?),
150 7 => Name::Global(NameMap::new(reader)?),
151 8 => Name::Element(NameMap::new(reader)?),
152 9 => Name::Data(NameMap::new(reader)?),
153 10 => Name::Field(IndirectNameMap::new(reader)?),
154 11 => Name::Tag(NameMap::new(reader)?),
155 ty => Name::Unknown {
156 ty,
157 data,
158 range: offset..offset + data.len(),
159 },
160 })
161 }
162}
163